#include <fstream>
#define LL long long
#define MAXK 25
using namespace std;

LL n, k, e[MAXK], sol;

int main()
{
	ifstream f("light2.in");
	ofstream g("light2.out");
	
	f >> n;
	
	f >> k;
	
	for(int i = 1; i <= k; ++i)
		f >> e[i];
	
	for(LL i = 2; i <= n; ++i)
	{
		int cont = 0;
		
		for(int j = 1; j <= k; ++j)
			if( ! (i % e[j]) )
				++cont;
		
		if(cont % 2)
			++sol;
	}
	
	g << sol;
	
	f.close();
	g.close();
	
	return 0;	
}